I have just installed FDM on a new machine, and tried setting it up to monitor downloads in Chrome. I checked the Chrome checkbox under Monitoring in FDM, and when it asked for the plugins directory, I had to create one under Users\Me\AppData\Local\Google. There was no Application dir, so I created that and Plugins under it. FDM then put it's dll there.
Also, acting on advice I found somewhere via a Google hit, I installed Chrome's Downloaders extension, and after installing the FDM plugin, was able to activate FDM in this plugin.
Yet, still nothing: When I click any link to download, Chrome's default, built-in download manager starts the download. How hard can this be to get right? What am I missing?